Enhancement of thermoelectric performance of Al doped PbTe-PbSe due to carrier concentration optimization and alloying

• Published in: Journal of alloys and compounds 2019-06, Vol.791, p.786-791
• Main Authors: Sun, Hao, Cai, Bowen, Zhao, Peng, Yu, Fengrong, Zhang, Long, Yu, Dongli, Tian, Yongjun, Xu, Bo
• Format: Article
• Language: English
• Subjects: Alloying; Alloying effects; Carrier density; Doping; High pressure synthesis; Intermetallic compounds; Lead base alloys; Lead selenides; Lead telluride; Optimization; Plasma sintering; Spark plasma sintering; Thermal conductivity
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.04.001

Al doped PbTe-PbSe alloys were successfully prepared with high pressure synthesis followed by spark plasma sintering. The incorporation of Se shows a dual effect on the system. Firstly, the carrier concentration can be further modified with varying Se content, on the basis of Al doping. Secondly, the lattice thermal conductivity can be greatly suppressed due to the alloying effect. Beneficial from this, the average ZT of AlxPbTe1-ySey samples are remarkably enhanced compared with the unalloyed ones. The highest average ZT of 0.82 is achieved in Al0.02PbTe0.75Se0.25, which is 60% higher than that of Al0.02PbTe. Combining strategies of dynamic doping and/or hierarchical phonon scattering, the thermal performance of n-type PbTe-based materials may be further enhanced. •N-type aluminum doped PbTe-PbSe compounds are synthesized under high pressure.•By Se alloying, the lattice thermal conductivity is significantly suppressed to 0.46 Wm−1K−1 in Al0.02PbTe0.5Se0.5 sample.•For the proper n, relatively high ZTavg values above 0.7 are obtained in Se alloying samples.•The highest ZTavg value of 0.82 is achieved in Al0.02PbTe0.75Se0.25 sample, and a 60% improvement compared with Al0.02PbTe.